Vehicle control system for minimizing fuel consumption

Abstract

A control unit of a vehicle control system estimates running-condition of a vehicle for a predetermined estimation period. A fuel-amount estimating portion estimates an engine condition related to a cooling efficiency, based on the estimated running condition. The control unit estimates multiple possible control patterns and calculates evaluation values related to the cooling efficiency for respective cases, in which a compressor is operated in accordance with each of the control patterns. The control unit selects one of control patterns to actually operate the compressor in accordance with the selected control pattern, so that fuel consuming amount can be reduced.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application is based on Japanese Patent Applications No. 2011-253976 filed on Nov. 21, 2011 and No. 2012-160768 filed on Jul. 19, 2012, the disclosures of which are incorporated herein by reference.TECHNICAL FIELD[0002]The present disclosure relates to a vehicle control system, according to which an operating condition of a driving source for a vehicle is estimated so as to optimize fuel consuming amount. The fuel consuming amount is necessary for the driving source to operate in-vehicle accessories, such as, an electric-power generator, a compressor for a vehicle air-conditioning apparatus and so on.BACKGROUND[0003]A vehicle control system is known in the art, for example, as disclosed in Japanese Patent Publication No. 2009-29344. According to the vehicle control system (JP No. 2009-29344), a time period is increased for a coast-lock-up operation and a fuel-cut operation in order to improve fuel consumption ratio. In addition, an op...

AI Technical Summary

Benefits of technology

[0032]According to the above feature, the vehicle running condition is estimated not only in a specific condition (such as, a running condition shortly before vehicle deceleration) but also in a normal condition, for a predetermined estimation period. The control pattern, which has a high operation efficiency for the accessory device, is calculated and / or selected depending on the estimated vehicle running condition. The accessory device is operated in accordance with such control pattern, so that fuel consuming amount for operating the accessory device can be minimized for almost all operating period of the accessory device. As a result, fuel consumption ratio for a driving source (such as, an engine) can be largely improved.

[0118]Accordingly, it is possible to optimize trade-off between the drivability and the fuel consumption ratio.

Problems solved by technology

The heat cost is a fuel consuming amount necessary for generating a unit amount for heat of cooling (a unit amount for cooling energy) by an operation of a refrigerating cycle.

When supply of refrigerant from a compressor to the cool-storage device is stopped in the vehicle deceleration period, a braking distance of a vehicle may be increased or discomfort may be given to a vehicle passenger because a braking torque by the compressor disappears due to stop of the compressor operation.

In the above prior art, the compressor operation is stopped in the vehicle deceleration period, when the cooling energy is fully stored in the cool-storage device and thereby it becomes impossible to further store the cooling energy in the cool-storage device.

Even when the discharge amount of the refrigerant is increased in the case of the estimation for the vehicle decelerating operation, the cooling efficiency of the air-conditioning apparatus may be low depending on various vehicle condition and other circumstances.

Therefore, the fuel consumption ratio may be adversely affected in some of the cases.

In other words, if the discharge amount of the refrigerant is increased in the vehicle decelerating period and if the cooling efficiency during such operation is lower than the average cooling efficiency, the fuel consumption ratio may be adversely affected.

In other words, when the air-conditioning apparatus is operated in such a way that the cooling energy is stored in the cool-storage device only in the period of the fuel-cut operation or in the vehicle decelerating operation, the effectiveness for reducing the fuel consuming amount cannot be sufficiently increased.

None of the above prior arts (JP No. 2009-12721, JP No. 2010-30497, JP No. 2005-207321) does disclose how to further improve the fuel consumption ratio.

When an alternator, which is driven by the engine, is provided in the vehicle as one of accessory devices, the fuel consumption ratio may be likewise adversely affected unless the operation of the alternator is properly controlled.

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